Mr Putin's decree names Rosatom chief Sergei Kiriyenko, 54, as the Kremlin's first deputy chief of staff in charge of domestic politics, responsible for formulating a broad range of policies.

Mr Kiriyenko replaces Vyacheslav Volodin, who was named the speaker of the newly-elected lower house.

While Mr Volodin has largely stayed out of the public eye, he has been widely seen as one of Russia's most influential officials, a puppet master who directed parliament's work and engineered elections.

The 52-year-old has become known for his statement: "There is no Russia without Putin."

Mr Volodin emphasised the need for consolidation "in the face of unprecedented pressure on our country," a reference to the escalating strain in Russia-West ties over Syria and Ukraine.

Like his predecessor, Mr Kiriyenko is expected to wield broad informal powers, reaching out to various sectors of Russian officialdom.

Mr Kiriyenko shot to prominence in 1998 when he became Russia's youngest prime minister at the age of 35, but lost his job four months later amid a financial crisis.

He later served as Mr Putin's regional envoy to the Volga River region before being put in charge of Rosatom in 2005.

He cut an image of an efficient technocrat, negotiating various high-profile nuclear agreements and often accompanying Mr Putin on his trips abroad.

Stanislav Belkovsky, a political consultant with ties to the Kremlin in the past, described Mr Kiriyenko as a "bureaucrat with a liberal image" who will "impeccably fulfil all Putin's decisions".

Mr Belkovsky also predicted that Mr Volodin may retain his influence.

Mr Volodin's predecessor, Sergei Naryshkin, has been named the new chief of the Russian Foreign Intelligence Service (SVR), a clear demotion.

The SVR is considered far less influential than the main KGB successor agency, the Federal Security Service, known under its Russian acronym FSB, which focuses on domestic security issues such as fighting terrorism, catching foreign spies and uncovering economic crimes.

Mr Naryshkin has reportedly has known Mr Putin since the late 1970s, when both were students in the KGB academy, and his new appointment was the latest move in an ongoing Kremlin reshuffle that has seen many old-time Putin associates lose their jobs to younger, low-profile aides.